Methanol, CH3OH, is used as race car fuel.How many kilojoules are released by burning 50.0 g of methanol?

Verified step by step guidance

1. Identify the chemical reaction for the combustion of methanol: \( 2 \text{CH}_3\text{OH} + 3 \text{O}_2 \rightarrow 2 \text{CO}_2 + 4 \text{H}_2\text{O} \).
2. Determine the molar mass of methanol (CH₃OH) by adding the atomic masses of its constituent atoms: C (12.01 g/mol), H (1.01 g/mol), and O (16.00 g/mol).
3. Calculate the number of moles of methanol in 50.0 g by dividing the mass by the molar mass of methanol.
4. Use the standard enthalpy change of combustion for methanol, which is typically given in kilojoules per mole, to find the energy released per mole of methanol burned.
5. Multiply the number of moles of methanol by the enthalpy change of combustion to find the total energy released in kilojoules.

Key Concepts

Combustion Reaction

A combustion reaction is a chemical process in which a substance reacts rapidly with oxygen, producing heat and light. In the case of methanol (CH3OH), its combustion yields carbon dioxide (CO2) and water (H2O), releasing energy. Understanding this reaction is crucial for calculating the energy released during the burning of methanol.

Molar Mass

Molar mass is the mass of one mole of a substance, expressed in grams per mole (g/mol). For methanol, the molar mass is approximately 32.04 g/mol. This concept is essential for converting the mass of methanol (50.0 g) into moles, which is necessary for determining the energy released during its combustion.

Enthalpy of Combustion

The enthalpy of combustion is the amount of energy released when one mole of a substance is completely burned in oxygen. For methanol, this value is typically around -726 kJ/mol. Knowing this value allows us to calculate the total energy released from burning a specific mass of methanol by using the number of moles derived from its mass.